The closest prior art of which the inventor is aware is his prior U.S. Pat. No. 4,286,311 (Anthony Maglica, "Flashlight", Ser. No. 968,468, filed Dec. 11, 1978). The flashlight described includes an adjustable light beam which may be focused by axially moving the bulb relative to the light reflector. The head mechanism includes a rotatable head member, a light reflector having a central opening, and having a cam surface extending rearwardly from the rear portion, a bulb carrier sleeve, axially movable through the central opening in the light reflector, and a cam follower roller, connected to the bulb carrier sleeve. When the head member is rotated through less than one revolution, the cam follower roller follows the light reflector cam surface, and the bulb carrier sleeve and bulb move axially relative to the light reflector, so as to adjust the light beam between a narrow or spot beam and a broad or flood beam.
The light reflector, moves axially during rotation of the head member, by virtue of its screw thread connection to the head member, affecting the desired axial movement of the bulb relative to the light reflector for adjustment of the light beam. Rechargeable batteries are an efficient power source for use with such a flashlight, and such batteries may be conveniently used in conjunction with a system for recharging the batteries while the batteries are in the flashlight. Further, a high intensity bulb, such as a halogen bulb, is an efficient light source for use with such a flashlight. Such bulbs, however, generate substantial quantities of heat, which may damage an unprotected lens, particularly in an adjustable beam flashlight where the bulb is axially movable into close proximity with the lens.